Screw-point for well-tubings.



J. WALLACE.

SCREW POINT FOR WELL TUBINGS.

APPLICATION FILED MAY t9. I916.

1 3 928 Patented Oct. 31, 1916.

JOHN WALLACE, OF HOUSTON, I! 1 SCREW-P0131 1 FOR WELL-TUBINGB.

LQUWAWS.

Specification of Letters Patent.

Patented Oct. 3t, iaie.

Application filed May 19, 1916. Serial No. 98,581.

To all whom it may concern Be it known that I, JoHN WALLACE, a citizenof the United States, residing at Houston, in the county of Harris andState of Texas, have invented new and useful Improvements in ScrewPoints for Well- Tubings, of which the following is a specification.

This invention relates to a screw point for well tubing, and one of itsobjects is to provide a screw point or anger which is designed to befastened to the end of the well tubing to facilitate its passage downinto the earth in the operation of boring a well, and which when thebore is completed may be allowed to remain as a fixed support for thelower end of the well tubing.

Another object of the invention is to provide a screw point or auger ofnovel and improved construction which is designed to easily cut its wayinto the earth in the operation of drilling the well, and which isdetachably coupled to the tubing in such manner as to permit removal ofthe tube in the event of a failure 'to strike water or other fluid, orto enable the tubing to be cleaned when choked with sand or othermaterial.

A still further object of the invention is to provide a drill point forwell tubing which embodies a thin spiral cutting flange, without taperand of a comparatively low pitch, approximately a twenty-two degreepitch, and which is compoundly curved, so as to cut with ease throughclay and other gummy and dense soils and lift and back the same tofacilitate the drilling action, thus obviating the well known objectionsto tapered and spiral cutters of high pitch and some material thicknesswhich are liable to clog in attempting to out through earth of thecharacter described.

The invention consists of the features of construction, combination andarrangement of parts hereinafter fully described and claimed, referencebeing had to the accompanying drawing in which:

Figure 1 is a side elevation of the device. Fig. 2 is a verticallongitudinal section on the line '22 of Fig. 1. Fig. 3 is a horizontaltransverse section on the line 3-3 of Fig. 1. Fig. 4 is a horizontaltransverse section on the line H of Fig. 1.

In carrying my invention into practice, I provide a drill or screw point1 composed of cast iron, steel or other suitable material, andcomprising a body portion formed of a series of stepped surfaces 2, 3, 4and 5 of gradually decreasing diameters, and terminating in a conicalentrance point 6. The portions of different diameters will vary, ofcourse, in number according to the length of the drill point, but inevery case Wll be of gradually diminishing diameter downward andgradually increasing diameter upward, for a purpose hereinafterdescribed. The portions 2, 3, 4t and 5 are preferably cylindrical inform, as shown, in order to secure a desired action on the loosenedearth.

The stepped portion of the body of the drill is provided with a cuttingblade 7, of

spiral formation, and extending continuously from the top of the portion2 to the middle portion of the point 6, and provided at its lowerextremity with a depending V- shaped cutting edge 8. This blade is inthe form of a comparatively wide and thin plate, of low spiral pitch,preferably about twenty-two degrees, and which is devoid of a taperingformation, that is increasing thickness toward the stock, beingapproximately of the same thickness throughout The blade is, however,compoundly curved each of its convolutions being provided with anelevated or crest portion 9 between adjacent convolutions, so as toefiect a desired and efficient lifting and loosening action upon thesoil.

As a result of the described construction of the drill, the tendency ofdrills having a general longitudinal taper or blades of tapered formincreasing in thickness toward the stock to clog and bind in the earth,is avoided, such action being due to the tendency of the material topack between adjacent convolutions and thus ofier a bindrance to thecutting action of the drill and its passage through dense and hardmaterials. By using a blade which is in the form of a plate of equalthickness throughout the objection mentioned is not only overcome, but abroad shelf is provided on which the dirt may lodge, and as the blade iscompoundly curved it will exert a lifting and loosening action on theearth with obvious advantages. Furthermore, by providing a stock withstepped portions of gradually increasing diameters upward, the earth cutand loosened up by the drill will be gradually forced outward as itaccumulates and compact against the sides of the well to graduallyincrease the density'as the drilling action proceeds. Thus While thedrill may cut its way with ease and freedom even; through heavy earth,such as clay and guminy soils it will be seen that the drill; will packitself in place and thus is adapted to form a stable bottom support forthe well tubing.

The body or stock of the drill. is provided at its upper end with athreaded extension 10, which is of cylindrical form, and is adapted tobe engaged by the thread of a coupling sleeve 11, which is adapted toconnest the same with the lower threaded end 12 of the perforated screensection 13 of the well tubing, whereby upon the drilling of the well thedrill point may be left in position to farm mable fixed support for thelower end of the well tubing. For the purpose or providing a secureconnection between the extension 10 and sleeve 11, the said extensionand sleeve are provided with coinciding tapering slots 14 to receive awedge key 15, whereby the drill is locked to the coupling member againstany possibility of casual disconnection during the drilling action atall other times except when it is desired to efiect a release of thetubing and a coupling projection at its opposite end, said stockcomprising a body having stepped portions of gradually increasingdiameters upwardly, and a spiral cuttin blade encircling said steppedportions sai blade being in the form of a plate of equal thicknessthroughout'and of a low spiral pitch, said blade having its convolutionsunited by compoundly curved lifting portions.

In testimony whereof ll aflix my signature.

JOHN r WALLACE.

Witnesses I I H. P. MEssEReAU, PHILIP THARR;

